Decreased uptake of GABA by dorsal ganglia in methylmercury-treated rats.

The uptake of 14C-GABA and 14C-choline by cerebral cortex slices did not show any change in rats which showed neurological signs 7 days after the last 7 methylmercury injections (10 mg/kg/day). However, 14C-GABA uptake by dorsal ganglia greatly decreased, although 14C-choline uptake did not decrease in dorsal ganglia. 14C-GABA uptake by cerebellum also was somewhat decreased. The degree of inhibition of 14C-GABA uptake by dorsal ganglia increased each day after the commencement of methylmercury injection. The decrease of 3H-GABA uptake by dorsal ganglia of methylmercury-injected rats was confirmed by autoradiography. Autoradiographic and inhibitor studies showed labelled GABA accumulated in the satellite glial cells. In vitro addition of methylmercury (10(-4)-10(-5) M) equally inhibited the uptake of GABA and choline by brain and dorsal ganglia slices. These studies may reveal a possible mechanism of methylmercury neuropathy.